Treatment of regenerated cellulose fabrics with urea-alkali-zincate solution



Patented Oct. 24, 1956 TREATMENT OF REGENERATED CELLULOSE FABRICS WITH UREA-ALKALI-ZINOATE SOLUTION Charles L. Mantell, Manhasset, and Theodore J. Dabrowskl, Kew Gardens, N. Y., assignors to United Merchants & Manufacturers, Inc., Wilmington, Del., a corporation of Delaware No Drawing. Application May 10, 1949, Serial No. 92,512

19 Claims.

This invention relates to the treatment of regenerated cellulose fabric or fabric containing regenerated cellulose and has for its primary object a method of modifying the normal characteristics of spun and/or filament regenerated cellulose goods to the end oil-producing a fabric of enhanced value and utility, the method requiring no complicated or special equipment for its practice and being otherwise economical to carry out. As hereinafter described in greater detail, the invention contemplates the treatment of the fabric with a solution which, in more or less noticeable degree according to the character of the fabric and the method employed, produces some or all of the effects of modifying the shrinkage characteristics of the fabric, rendering the fabric stifl'er and somewhat translucent, and, in the case of spun regenerated cellulose goods, eliminating fuzz.

The invention contemplates a process of treating regenerated cellulose fabric with a solution containing caustic zincate and urea, hereinafter referred to as the treating solution, there being obtained a fabric having, among other eflects, appreciably modified shrinkage characteristics; that is, it shows a substantially reduced shrinkage by comparison with the normal shrinkage of It has further been observed that the treated fabric tends to become stifier by comparison with the untreated fabric. This characteristic of stiffness is highly desirable in certain materials, for example, in curtain and table goods, and in certain types of dresses and blouses, e. g., lawns and organdies.

As described, the treating solution is composed of caustic zincate and urea. It may be prepared the untreated fabric, considering such normal shrinkage to be the initial wash shrinkage. 'In addition, in the case of spun regenerated cellulose, the treated fabric has a more clear-cut and attractive appearance. Thus, when the untreated fabric is held up to the light and examined, i. e., held between the light and the eye, it presents a misty appearance due to the lack of sharp definition of the warp and weft thread outlines which results from the fuzz on the threads. This characteristic is particularly evident when such fabrics are used, for example, as curtains. It has been found, according to this invention, that if the fabric is treated as described. its appearance is quite radically changed. When a fabric so treated is held up to the light and examined as before, it is observed that the threads are sharply outlined, there being substantially no evidence of fuzz. It has also been observed in some instances that, notwithstanding the sharpening of the outlines of the threads. the body of each thread assumes a somewhat translucent character. As will be understood,

'these last-mentioned efiects willeach be more or less noticeable and ofvarying practical consequence depending on the character of the fabric and the use to which it is put; but, for convenience, they may be described as bringing abouta clarification of the fabric.

by mixing together an aqueous solution of urea and an .alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate; or by adding zinc oxide to an aqueous solution of an alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, sodium zincate and potassium zincate respectively being formed, and then incorporating the urea. It is to be understood that in referring to the zinc oxide content of the solution it is intended to include the oxide added as such or as comprised in the alkali metal zincate added to the solution or formed therein. Compounds which, when added to a caustic zincate solution, hydrolyae to form urea, may be used in making up the solution. Such compounds may include, for examples, cyanamide, guanidine,

' guanylurea, etc. In the premises, it will be understood that the term "urea as used herein is intended to include urea per se and also compounds which produce urea in the foregoing manner. Furthermore, in place of urea per se or the urea-forming compounds as described, other compounds may be employed if desired as one of the components in the .present treating solution as, for examples, the alkali metal thiocyanates; sodium thiocyanate, potassium thiocyanate or ammonium thiocyanate, and the polyamines; ethylene dlamine or hexamethylene-tetramine. The amount of urea may be varied from about 3 to about 15% by weight, preferably from about 10 to about 15%. Zinc oxide, whether added as such or in the form of the zincate, may be present in amounts ranging from about 1 to about 4% by weight, calculated as zinc oxide; while the caustic may be varied from about 9 to about 18% by weight or more, although the use of higher concentrations of caustic generally does not justify, the added expense involved. If sodium hydroxide is employed as the caustic, a preferred concentration is from about 9 to about 13%; for potassium hydroxide, a preferred rangeis from about 12 to about 18%. The effects are decreased by going below these minimum concentrations;

3 about 2% zinc oxide, and about sodium hydroxide.

In treating regenerated cellulose fabric or fabric containing such regenerated cellulose, according to the present invention, the solution may be applied simply by immersing the fabric in the solution, although any other suitable method may be employed as, for examples, by pouring the solution on the material or by padding or rollers. The fabric may or may not be under tension during the application of the! solution. The time of treatment may range from about 10 seconds to about 90 seconds, preferably from about 10 seconds to about 1 minute, this being known as the action time of the solution. It extends from the point at which the material is put into the solution or otherwise brought into contact therewith, until it is flushed of the same. The fabric, of course, is actually immersed in. the solution for a lesser interval than the action time or for a period from about 1 second up to about 85 seconds. Treating temperatures may range from about 68 to about 90 1''. although higher and lower temperatures, say from the freezing point to about 120 F., may be employed; After immersion the fabric is preferably, but not necessarily, squeezed and framed to a desired width, for example, on a tenter frame. At the end of the solution action time the fabric is adequately flushed, preferably with hot water or a dilute solution of sulfuric acid, acetic acid, sodium bicarbonate or other suitable neutralizing agent to neutralize the fabric and set the yarns at the crossing points in the goods. Thereafter the material may be dried, preferably at an elevated temperature by means of hot air. It is desirable, but not essential, that the flushing or neutralizing steps and the drying take place while the goods are framed to the desired width. Best results are obtained when the material is held under tension during these steps of the procedure. The following examples illustrate the method and results obtained in controlling the shrinkage of regenerated cellulose material:

Example 1 Spun rayon marquisette was run through a solution made from about 9% caustic, 1.8% zinc oxide, and 10% urea during an interval of about .5 seconds at room temperature, squeezed by C. C. C.T-l91a, (page 17, section 3). The results are as follows:

Warp Filling Original Cloth, Per Cent 10.0 13.1 Treated Cloth, Per Cent 1.3 2. 7

In the foregoing example the visual characteristics of the treated cloth are appreciably altered. By comparison with the'original material, the treated cloth has a cleaner thread outline and an overall translucent appearance. These effects are produced in addition to the effect of shrinkage or dimensional stability. The follow- 4 ing example shows with greater particularity the stiifness and translucency effects obtainable by the invention:

Example 2 A number of solutions of varying urea concentration were made up and the shrinkage of rayon marquisette determined for each solution. The procedure of Example 1 was employed in each Samples of spun rayon marquisette were treated in a number of urea-caustic zincate solutions of varying concentrations. The method of processing the cloth was the same as that described in Example 1, except that an immersion time of about 30 seconds was employed. Stiffness tests were then made, the stiffness being reported as the force in grams exerted by the treated sample when bent to a 40 angle. The translucent effect produced by the various solutions was observed and is reported here in a qualitative way, i.e., by comparing one sample with another. Following are the data obtained:

Solution Composition Run Stiffness, 23$ NaOH, ZnO, Urea, Emma Eflect Per Cent Per Cent Per Cent 9 l 10 0.83 11 1 10 1. l0 moderate. 13 1 10 1.0 Do.

9 2 10 0.4 11 2 10 1.0 Do. 13 2 10 0.9 good.

9 3 10 0.65 11 3 10 l. 05 moderate. 13 3 10 1.2 good.

9 4 10 0.45 11 4 10 0.02 moderate. 13 4 10 1.3 goo l0 2 10 1.4 Do.

As will be observed, the stiflness effect is of a high order. The finish of the cloth treated as in the foregoing example, by which is included its general clarified appearance, has been found to be permanent to washing. Cloth with this kind of finish is especially desirable for sheer curtain materials, such as marquisettes, ninons, etc.

Example 4 Samples of filament rayon marquisette were held under moderate tension on a frame and treated at room temperature with solutions of varying concentrations as appear below. The so.. lutions were poured over the fabric for about either 10 seconds or 1 minute as indicated. Thereafter the fabrics were washed with hot water, removed 'dilute acetic acid. rinsed witheold water. re'

Solution Composition Shrinkage Sample No. Time I NaOH Z110 Urea Warp Filling Per Per Per Per Per cent cent ml real can! i.. 10 sec. 9 1 3 7.2 4. n 9 l 15 4.0 6. 8... n is 4 9 6.0 o 13 4 16 5.1 9. n 10 I 8.3 i 8. n 10 2 8 7.4 4. 7--. In 10 3 10 4.6 5. 9-... lmin l0 2 l0 4.l 3. l0 9 is 4.2 6. l0.-. n 10 0- 0 14.0 6. u..- n 10 v o 10 11.1 4. l2... n 0 0 0 l6,4 is.

A practical application for producing translucency eifccts by this invention is in the making of simulated damask from regenerated cellulose fabric. In this process the fabric is ilrst printed in a suitable design with a resin gum paste, such as dextrine or British gum, and then passed in scribed above. After squeezing, the fabric may beaired or allowedtopileupinaJ-boxoron a traveling belt for about A to about minutes, then framed to a desired width and washed and neutralized as described. After all the gum has been washed out of thegoods they may be iinished in the normal manner and framed out to width. If desired. an organic acid, e. g. acetic. propionic. etc., may be added to the gum or paste to aid in retarding the action of the treating sositlcoted from the ..class consisting of sodium zincate and potassium zincate and equivalent to about 1 to about 4% by weight of zinc oxide, and about 9 to about 18% by weight of an alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, for a time of treatment ranging from 1 about .10 seconds to about 1 minute. thereafter stretching the fabric, flushing said solution from the fabric and drying the some while in the stretched condition. I I

2. Process according to claim 1 in which the urea concentration of the solution is about to about 16% by weight.

alkalimetalhydroxide v I s .Processaccordingtoclaim4inwhichthe- I open width through the treating solution as de-.

- urea concentration of the'solution ywelght.

4.Processaccording sodium hydroxide.

alkali metal hydroxide is sodium hydroxide.

9. In, the process of-producing damask 'eilects upon regenerated ceilulosefabric,whiohcomprisss printing selected areas of the fabric with aresistgum paste and then subjecting the printed fabric to the action of a treating agent, the immovement which comprises employing as the' treating agent an aqueous solution comprising about 3 to about 15%by weight of urea. an alkali metal zincate selected from the class consisting of sodium zincate and potassium zincate and equivalent to about 1 to about 4% by weight of xinc oxide, and about 9 to about 16% by weight of an alkali metal hydroxide selected from the class consisting of sodium hydroxideand potassium hydroxide, treating the fabric with said solution for a time ranging from about 10 seconds to about 1 minute, thereafter stretching the fabric, and washing and drying the same while in-the stretched condition.

10. Process according to claim sin which the urea concentration of the solution is about 10 to about 15% by weight.

11. Process according to claim 9 in which the urea concentration of the solution is about 10% by weight. v I

12. Process according to claim 9 in which th alkali metal hydroxide is sodium hydroxide.

13. Process according to claim 1 in which the alkali metal zincate is sodium zincate and in which the alkali metal hydroxide is sodium hydroxide.

14. Method of modifying fabric containing reweight of zinc oxide. about 9 to about 13% by weight of sodium hydroxide and the balance water, for a time ranging from about 10 seconds to about seconds, thereafter stretching the fabric and flushing the solution therefrom.

15. Method of modifying fabric containing regenerated cellulose which comprises treating the fabric with an aqueous solution of from about 3 to about 15% by weight of urea, potassium zincate equivalent to about 1 to about 4% by' weight of zinc oxide, about 12 to about 18% by weight of potassium hydroxide and the balance water, for a time ranging from about '10 seconds to about 90 seconds, thereafter stretching the fabric and flushing the solution therefrom.

16. Process of inhibiting the wash shrinkage of fabric containing regenerated cellulose which comprises treating the same with an aqueous solution comprising from about 3 to about 15% by weight of urea, sodium zincate equivalent to from about 1 to about 4% by weight of zinc oxide, from about 9 to about 13% by weight of sodium hydroxide,,and the balance water, for a time ranging from about 10 seconds to about 90 seconds,andthereafterflushingthesolutionfrom the fabric and drying the same.

17. Method of modifyina fabric containing regenerated cellulose which comprises treating the same with an aqueous solution of from about 3 to about 15% by weight of urea, sodium zincate equivalent to from about 1 to about 4% by weight of zinc oxide, from about 9 to about 18% by weight of sodium hydroxide, and the balance water, for a time ranging from about 10 seconds to about 90 seconds, and thereafter flushing the solution therefrom.

18. Method of modifying fabric containing regenerated cellulose which comprises treating the same with an aqueous solution of from about 3 to about 15% by weight of urea, potassium zinoate equivalent to from about 1 to about 4% by weight of zinc oxide, from about 9 to about 18% by weight of potassium hydroxide, and the balance water, for a time ranging from about 10 seconds to about 90 seconds and thereafter flushing the solution therefrom.

, 19. Method of modifying fabric containing regenerated cellulose which comprises treating the same with an aqueous solution of from about 3 to about 15% by weight of urea, an alkali metal zincate selected from the class consisting of sodium zincate and potassium zlncate in an amount equivalent to from about 1 to about 4% by weight of zinc oxide, from about 9 to about so 18% by weight of alkali metal hydroxide selected from the class consisting of sodium hydroxide and potassium hydroxide, and the balance wawr, for a time ranging from about 10 seconds to about 90 seconds and subsequently flushing the solution therefrom.

CHARLES L. MANTELL.

THEODORE J. DABROWSKI.

REFERENCES CITED The following references are of record in file of this patent:

UNITED STATES PATENTS Number Name Date 1,680,865 Weber May 31, 1555:? 1,661,879 De Goncz Mar. 6, 1923 1,998,579 Heberlein Apr. 23, 193% 2,129,708 Schreiber Sept. 18, 1938 2,142,043 Boyd Dec. 27, 193% 2,203,375 Weiss June 4, 194% FOREIGN PATENTS Number Country Date 20,314 Great Britain 1835 286,488 Great Britain Feb. 24, 102"? 518,843 Great Britain Jan. 12, 19 54? OTHER REFERENCES Katz et al., Rayon Text. Mo., Dec. 1940, pages 54. 55. 

1. PROCESS OF MODIFYING REGENERATED CELLULOSE FABRIC WHICH COMPRISES TREATING SAID FABRIC WITH AN AQUEOUS SOLUTION COMPRISING ABOUT 3 TO ABOUT 15% BY WEIGHT OF UREA, AN ALKALI METAL ZINCATE SELECTED FROM THE CLASS CONSISTING OF SODIUM ZINCATE AND POTASSIUM ZINCATE AND EQUIVALENT TO ABOUT 1 TO ABOUT 4% BY WEIGHT OF ZINC OXIDE, AND ABOUT 9 TO ABOUT 18% BY WEIGHT OF AN ALKALI METAL HYDROXIDE SELECTED FROM THE CLASS CONSISTING OF SODIUM HYDROXIDE AND POTASSIUM HYDROXIDE, FOR A TIME OF TREATMENT RANGING FROM ABOUT 10 SECONDS TO ABOVE 1 MINUTE, THEREAFTER STRETCHING THE FABRIC, FLUSHING SAID SOLUTION FROM THE FABRIC AND DRYING THE SAME WHILE IN THE STRETCHED CONDITION. 